Programming by Coincidence (Part 2)

There is only one way to avoid all these accidents: Always program deliberately.

How to Program Deliberately

• Always be aware of what you are doing. Never let things go out of your hand.
• Don’t code blindfolded. Chances of coincidence are high when we try to build an application without fully understanding it.
• Always proceed from a plan. It doesn’t matter whether the plan is in paper or in your mind.
• Rely only on reliable things. Do not depend on accidents or assumptions.
• Document your assumptions. This helps to recollect and validate the assumptions at a later point of time.
• Don't just test your code, but test your assumptions as well. Write assertions to test your assumptions. Never guess anything; actually try it.
• Prioritize your effort. Spend time on important aspects.
• Don’t be a slave to history. Always be ready to refactor. Never let what you have already done constrain what you do next.

- summary of Programming by Coincidence, from The Pragmatic Programmer: from Journeyman to Master